1. Field of the Invention
The present invention relates to an information reproducing apparatus and method such as a DVD player, a CD (Compact Disc) player or the like, and further relates to an error correction system for the information reproducing apparatus.
2. Description of the Related Art
Typically in the information reproducing apparatus such as a DVD player, a CD player or the like, a light beam to read information is irradiated from a laser device in an optical pickup onto an information recording medium such as a DVD, a CD or the like. A photodetector in the optical pickup receives the reflection light from a recording surface of the information recording medium to output a RF (Radio Frequency) signal and the like. The outputted RF signal is subjected to an equalizing processing and further to a binarization processing, a decoding processing, an error correction process and so on. Thereby, the output data through the error correction is obtained.
Specifically, the correction process may be of a scheme using the error correction data indicating the sum of data values in each row or in each column of the error correction data block arranged in a matrix of a certain range of the record data, the error correction data being recorded in addition to the record data. For the sake of convenience, herein, the error correction using the error correction data, which indicates the sum of data values in each row (i.e., each alignment in a lateral or horizontal direction), is referred to as a “C1 correction”, while the error correction using the error correction data, which indicates the sum of data values in each column (i.e., each alignment in a longitudinal or vertical direction), is referred to as a “C2 correction”.
Alternatively, there are other kinds of known error corrections such as a “multiple correction” represented by a “double correction” for executing the error correction using the error correction data or the record signal obtained as a result of a double reading by repeating a data reading twice with respect to the same recording area, or a “quadruple correction” for executing the error correction using the error correction data or the record signal obtained as a result of a quadruple reading by repeating a data reading four times with respect to the same recording area.
Nevertheless, in the conventional information reproducing apparatus mentioned above, only one among the error correction schemes is employed for the same kind of recording medium or the individual information reproducing apparatus. Similarly, the repeating number of the multiple correction is fixed with regard to the same kind of recording medium or the individual information reproducing apparatus. Additionally, parameters to define reproducing conditions for the information reproducing apparatus, such as a rotation number of a spindle motor, a characteristics setting of the equalizer and the like, are inherently fixed with regard to the same kind of recording medium or the individual information reproducing apparatus.
As a result, in spite of retrying the error correction by repeating the processes after the data reading, or increasing the volume of data as the basis of the error correction, immediately after the failure in obtaining the satisfactory result of the first error correction, the improvement in an error avoidance effect is extremely limited due to a remained cause of errors, unless the cause of errors is eliminated or reduced. With regard to some causes of errors, the improvement in the error avoidance effect is hardly expected, rather demerits from repeating the error correction, such as the increase in the processing time or the processing cost, become manifest.
As described above, the conventional information reproducing apparatus and method include the technical problem for the improvement in the error avoidance effect.